Firearm



H. LAUF FIREARM July 27, 1937.

2 Sheets-Sheet 1 Filed Nov. 21, 1934 H. LAJF July 27, 1937.,

FIREARM Filed Nov. 21, 1934 2 Sheets-Sheet 2 Patented July 27, 1937 UNITED STATES PATENT OFFICE Application November 21, 1934, Serial No. 754,100 In Sweden November 22, 1933 6 Claims. (Cl. 42-3) The present invention relates to an automatic firearm having a breech block, which for the purpose of locking is adapted to be tipped in the breech body or slid to a position parallel to the longitudinal axis, in which firearm, for the purpose of controlling the movement of the breech block, the latter is provided with a link member which is adapted to be actuated by a driving member. Upon firing, said driving member reciprocates parallel to the axis of the bore, so that the breech block becomes unlocked from the breech body, and drawn backward to open position actuated by said link member.

According to the invention the link member is also jointed to the driving member so .that by direct actuation of the driving member and the link member the breech block may be moved to its foremost position again and be pressed into locking engagement with the breech body.

The invention is illustrated in the accompanying drawings,- in which Figure 1 shows a vertical longitudinal section through part of the gun, the breech block being closed,

Figure 2 is a corresponding section, the breech block being fully open,

Figure 3 is a cross section taken on line III-J11 of Figure 2,

Figure 4 is a section taken on line IV-IV of Figure 1 and Figure 5 is a section taken on line V-V of Fi ure 2.

The following Figs. 6 to 9 show modifications of the above; and

Figure 6 is a detail section corresponding to Figure 1 and Figure '7 is a detail section corresponding to Figure 2.

Figure 8 is a section taken on. line VIII-VIII of Figure 6 and Figure 9 is a section taken on line IXIX of Figure 7.

Ina known manner the breech block i isslidable in the bore of the breech body 2 parallel to the axis of the bore. By means of a semi-circular protuberation 3, it is locked in its foremost position in the segment-shaped recess 4 of the breech body (Figures 2 and 3) by lowering the rear end of the breech block. The rear surface 60 I which is located at the tipping side and absorbs the forces at firing, and the corresponding abutment 2 of the breech body are slightly conical, so that the rear end of the breech block may be able to drop down completely in front of the 55 abutment 2 when swinging in a vertical plane about the axis 5 of a semi-spherical recess formed in the breech block with a corresponding projection or lug on the breech body. Subsequently, self-locking takes place in the breech body during the firing, due to the friction angle of the 5 locking surfaces l and 2 relative to the resultant of resistance W lying within the angle of friction.

The movements of the breech block are controlled by means of a link member 6, which by 10 means of the pin I3 is jointed with the rear forkshaped portion 8 of the breech block and by means of the pin 1 flexibly connected with the ear Ill of the gas piston 9. The gas piston is pressed constantly forward by means of the operating spring II, the rear end of which rests against a ring l2 of the guide sleeve, the piston and the link member moving the breech block I to the closed and locked position (Figure 1).

The link member is extended past the lower 20 pivot 13 and is there formed into a cam lever l4. During the opening movement after the release of the breech block, the said lever by an upward swinging movement of its rear end, caused by the link member 6 will rest against the cross 25 piece I5, the upper and lower ends of which rest firmly against the shoulder 2 of the breech body 2.- Thus, the pin l3 together with the whole breech block i and the cartridge ejector l6 (Figure 3) at the throwing back of the gas 30 piston 9, H are pulled back completely without shock by the front surface I4 of the cam lever, which surface is curved in a suitable manner. The lower end of the cross piece i5 then slides in the longitudinal grooves i8 of the breech body. 35 The member i5 forms a cross piece fixed to the striking pin l9 or made integrally with the same, the said cross piece being intended for cooperation with the cam surface I 4 for pressing in the striking pin. The cross piece may, however, 40 very well be dispensed with.

The surface I4 has its cam-like shape only for the purpose that the downwardly extending end of the link shall not be hindered in its movement at the swinging. It does not cooperate 45 with the locking bolt.

The striking pin l9 during firing is not thrown forwards immediately by the gas piston 9, I! but with the guide pipe 38 of the gas piston-9, I'I.

At their rear ends the two parts are united by means of the stirrup 28 the upper and lower ends of which are provided with hinges 39 for the piston casing 40. By means of the intermediate portion 4] of the casing and the bolt 43, the stirrup and casing are jointed together. In order to prevent 'the guiding sleeve 4 to be thrown out by the spring ll, during the turning down of the butt after drawing out the upper bolt 43, the sleeve 46 is turned so that a projection 45, Fig. 1,

' engages a recess in the gas piston 9 and thus is united with the latter. To guarantee this connection a protuberation 46 enters a recess in the piston casing 40, when the connection has been obtained. Thus, the piston casing may be completely closed only when the guide sleeve is locked in a correct way.

As shown in Figures 6 and 8 theiink member 6 may also be placed so far away from the breech body that the cam surface I4 thereof may swing directly up to the rear edge 55 of the breech body 2, while the crosspiece I5 is left out. The link member 6 in this embodiment is mounted on the shaft 1 in a recess 56 in the coupling member 51, which is rigidly connected with the gas piston II. The cross piece 58 of the coupling pulls back the striking pin 5950 by means of an extended portion at the under side thereof, so that no firing can take place when the breech block is not completely closed.

In this embodiment Figs. 6 and 8 the operating spring II is provided behind the coupling member 51 and with its rear end mounted in the butt. Its front portion is kept in position by means of the tube 44, the front portion of which is guided in the sleeve 52 by means of the guiding head M. The guiding head permanently presses the coupling piece 5'! forward by means of the spring H and throws also the striking pin forward, the projection 63 of the said guiding head acting upon the shoulder 60 of the striking pin.

The closing spring with its guide may be pushed back and blocked in the piston in some suitable manner -(not shown). All other parts of the breech block mechanism will then be easily removed from the gun after the piston has been turned down. Thus, this embodiment does not only make the cross piece superfluous but also makes the breech block sleeve shorter and simpler, but moreover facilitates the taking apart of the mechanism.

Having now described my invention, what I claim as new and desire to 1. In an automatic firearm having a breech body, the combination with a breech block mounted to be tipped around its front end in said breech body and normally locked therein, a driving member mounted to reciprocate in said breech body parallel to the axis of the bore upon firing of the firearm, a link member having a cam extension, a' fulcrum pin for securing said driving member to said link member, a pivot pin in said breech block for securing said link member thereto, whereby, during firing, the driving member swings said link member so that said cam extension will engage the breech body to release the breech block byraising its rear end from said locking engagement thus allowing retracting and forward movement-of said breech block.

2. An automatic firearm in accordance with claim 1 in which the cam extension of said link member is extended past the axis of said pivot pin and adapted, after the releasing movement, to rest with its free end against a fixed shoulder provided in the breech body.

3. An automatic firearm in accordance with claim 1, in which a locking surface is provided adjacent the rear end of the breech block and a corresponding locking abutment is provided in the breech body, both being slightly conical.

.4. In an automatic firearm in accordance with claim 1, a crosspiece on the breech block, a striking pin extending through the cross piece some distance past the same, whereby, said link member, during the last part of its swinging movement forward while closing the breech, is adapted to drive with its front surface the striking pin against the percussion cap.

5. An automatic firearm in accordance with I claim 1, in which said cam extension of the link member is extended past the ams of said pivot pin in the breech block and the breech body being provided with a fixed shoulder and the breech block with a cross piece and a striking pin extending through said cross piece some distance past the same, said cam lever being adapted, after the releasing movement, to rest with its free end against said fixed shoulder, whereby, said link member, during the last part of its swinging movement forward while closing the breech, is adapted to drive with its front surface the striking'pin against the percussion cap.

6. In an automatic firearm in accordance with claim 1, a crosspiece on the breech block, a striking pin extending through the crosspiece some distance past the same, whereby, said link member, during the last part of its swinging movement forward while closing the breech, is adapted to drive with its front surface the striking pin against the percussion cap, the rear end of said striking pin having an upward extension.

s new. 

